Reviewed by Geoff.

    Reviewed by Geoff.

        - fixed <rdar://problem/5197621> closing second window crashed webkit (13660)
        http://bugs.webkit.org/show_bug.cgi?id=13660

        No test case; not testable.

        * page/mac/FrameMac.mm:
        (WebCore::Frame::cleanupPlatformScriptObjects): Check if the interpreter is null;
        if so, we don't want to do work that may lazily create it while the Frame is being
        destroyed.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@21419 268f45cc-cd09-0410-ab3c-d52691b4dbfc